The present invention is directed to a multiple data channel wireless data coupling system for transmitting measured data from a plurality of rotating sources. More specifically each data channel has a unique carrier frequency which is modulated by a data source signal.
Wireless data coupling systems are well known as shown by U.S. Pat. No. 3,850,030 and 3,909,811 both of which are in the name of the present inventor and assigned to the present assignee. U.S. Pat. No. 3,909,811 is an example of a single channel multiplexed system. Where multiple data channels are desired separate carrier frequencies have been provided by the use of LC tuned oscillators. However, these are subject to drift necessitating a large frequency difference between channels and therefore fewer channels.
A relatively large number of data channels have been provided in a wired system by slip rings but there are problems of wear and convenient mechanical placement.